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US 9,805,435 B2Granted
Full color visibility model using CSF which varies spatially with local luminance
AssigneeDigimarc Corporation
InventorsAlastair M. Reed, Kristyn R. Falkenstern, David Berfanger, Yang Bai
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Abstract
The present disclosure relate generally to image signal processing, color science and signal encoding. Digital watermarking can be applied to color image data through use of a luminance contrast sensitivity function and a chrominance contrast sensitive function. Of course, other features, combinations and claims are disclosed as well.
Claims20
An apparatus comprising:
- memory for storing:
- i) a luminance contrast sensitivity function (CSF1), ii) a chrominance contrast sensitivity function (CSF2), and iii) data representing color imagery;
- and
- one or more electronic processors configured for:
- predicting degradation of image areas associated with an application of digital watermarking in the data representing color imagery by applying the CSF1 and the CSF2 to the data representing color imagery, in which the CSF1 varies depending on luminance values associated with local regions of the data representing color imagery and in which the CSF1 is used for processing luminance data and the CSF2 is used for processing chrominance data;
- altering the data representing color imagery with digital watermarking, in which the digital watermarking is guided based on results obtained from said predicting including predicted degradation of image areas, wherein the digital watermarking uses weightings associated with local regions of the data representing color imagery, said altering yielding locally varied digital watermarked data representing color imagery.
3 more elements
A method comprising:
- obtaining color image data;
- altering the color image data with digital watermarking, the digital watermarking comprising an information signal, said altering yielding digital watermarked color image data;
- comparing the digital watermarked color image data to the color image data to determine a visibility map, the visibility map comprising a luminance contrast sensitivity function (CSF1) and a chrominance contrast sensitivity function (CSF2);
- weighting the digital watermarking according to the visibility map so that local image areas within the color image data are weighted differently, said weighting yielding weighted digital watermarking;
- altering the color image data with the weighted digital watermarking to yield locally varied digital watermarked color image data.
2 more elements
Dependencies are inferred from the claim text.